Shrub forms of hardy Proven Winners Hibiscus Plant, botanically known as Hibiscus syriacus, are commonly called rose of Sharon or althea. Like tropical hibiscus, it has woody stems and a bushy form. However, its flowers appear in great abundance, measure 2-3 inches across, can be single or double, and come in shades of pink, purple, blue and white-with some cultivars having a contrasting eye. Like perennial hibiscus, you won't find a rose of Sharon with yellow or orange flowers. Butterflies and hummingbirds are attracted to its blooms, particularly single forms, but deer typically pass it by.